Development of RP-HPLC Method for the Quantitative Estimation of Ofloxacin and Ornidazole in Combined Liquid Oral Dosage Forms

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1 1972 Int J Pharm Sci Nanotech Vol 6; Issue 1 April June 2013 International Journal of Pharmaceutical Sciences and Nanotechnology Research Paper Volume 6 Issue 1 April June 2013 MS ID: IJPSN VARUN Development of RP-HPLC Method for the Quantitative Estimation of Ofloxacin and Ornidazole in Combined Liquid Oral Dosage Forms G. Varun, B. Shyamkumar, M. Cylma * and N. Reema Shree Devi College of Pharmacy, Kenjar, Mangalore , Karnataka, India Received September 15, 2012; accepted February 20, 2013 ABSTRACT A simple, efficient and reproducible reversed phase high performance liquid chromatographic (RP-HPLC) method for the quantitative estimation of ofloxacin and ornidazole in bulk and in combined liquid oral dosage form has been developed and validated. The separation was carried out using thermohypersil phenyl column (250 mm 4.6 mm, 5 μm) as stationary phase with isocratic flow and phosphate buffer (adjusted to ph 2.4 with ortho phosphoric acid): acetonitrile (87:13 v/v) as mobile phase. Mobile phase was maintained at a flow rate of 1.0 ml/min and UV detection was carried out at 294 nm. The retention time of ofloxacin and ornidazole was and 5.69 min, respectively. All calibration curves showed good linear correlation coefficients within the tested limits (r 2 > ). The linear dynamic range was µg/ml and µg/ml for ofloxacin and ornidazole respectively. Percentage recoveries for ofloxacin and Ornidazole were % and % respectively. All the analytical validation parameters were determined and found in the limit as per the International Conference on Harmonization (ICH) guidelines, which indicates the validity of the method. The validated method is also found to be accurate, precise and robust for the quantitative estimation of ofloxacin and ornidazole in combined liquid oral dosage forms. KEYWORDS: Ofloxacin; Ornidazole; RP-HPLC; Quantitative Estimation; Method Validation. Introduction Ofloxacin (OFL) is a second-generation fluoroquinolone acting as antimicrobial agent. Chemically it is known as 7-fluoro-2-methyl-6-(4-methylpiperazin-1-yl)-10-oxo-4-oxa- 1-azatricyclo[ {5,13}]trideca-5(13),6,8,11-tetraene-11- carboxylic acid. Ornidazole (ORN) belongs to nitroimidazole class of drugs mainly used as tissue amoebicides, 1-chloro-3-(2-methyl-5-nitro-1H-imidazol-1- yl)propan-2-ol (Tripathi, 2008; Indian Pharmacopoeia, 2010). The chemical structure of ofloxacin and ornidazole are shown in Fig. 1 and 2 respectively (Indian Pharmacopoeia, 2010). Fig. 1. Chemical structure of Ofloxacin (OFL). Fig. 2. Chemical structure of Ornidazole (ORN). In the literature, there are few analytical methods reported for the estimation of ofloxacin and ornidazole as individual drug or in combination with same or other drugs in tablet dosage form by UV-Visible spectrophotometry (Barot et al., 2012; Daxina et al., 2011; Jawed et al., 2011; Kareti et al., 2011; Ramesh et al., 2011; Rege et al., 2011), HPTLC (Puranik et al., 2010), RP-HPLC (Darshan et al., 2012; Nalini et al., 2011; Pankaja et al., 2012; Rege and Ramesh, 2011), and simple Electro-Analytical Technique (Rege and Sathe, 2011). Literature survey reveals that there is few validated methods for simultaneous estimation of ofloxacin and ornidazole in combined liquid oral dosage form. The goal of the present study was to develop and validate RP-HPLC method for simultaneous analysis of ofloxacin and ornidazole in combined liquid oral dosage forms. 1972

2 Varun et al: RP-HPLC Method for the Quantitative Estimation of Ofloxacin and Ornidazole in Liquid Oral Dosage Forms 1973 Material and Methods Drugs and Chemicals Ofloxacin and ornidazole reference substances were provided by Dodel Analytical Lab., Vapi, Gujarat, India. Suspension dosage forms (O2-Suspension, Medley) were procured from the local market, each 5 ml containing 50 mg of ofloxacin and 125 mg of ornidazole. All reagents and solvents used for study were of analytical grade. Instrumentation Jasco-HPLC was used for experimental analysis, a manual injection facility with Rheodyne 7725i (fixed capacity loop of 20 µl), Jasco PU 980 HPLC pump. The chromatographic analysis was performed using Oracle 2, Sphinchrome CFR software, Version , Thermohypersil Phenyl column (250 mm 4.6 mm, 5 μm) as stationary phase, Jasco UV-975 was used for detection. In addition, Digital ph Meter (Toshniwal), Electronic Weighing Balance (Tapson s Analytical Balance), Ultrasonicator (TP-101) were used. Preparation of Mobile Phase Mobile phase was prepared by mixing 870 ml of potassium dihydrogen phosphate (KH2PO4) buffer (ph 2.4) and 130 ml of Acetonitrile (ACN) and filtered through 0.2 µm Supor 200 membrane filter using Vacuum Pump and ultrasonicated for 10 min for degassing. Ofloxacin (OFL) 50 mg of standard OFL was weighed and transferred to a 100 ml volumetric flask and dissolved in 35 ml of mobile phase. Then volume was made up to the mark with same solvent to obtain final concentration of 500 µg/ml of OFL and labeled as Standard Stock OFL. Ornidazole (ORN) 125 mg of standard ORN was weighed and transferred to a 100 ml volumetric flask and dissolved in 35 ml of mobile phase. The volume was made up to the mark with same solvent to obtain final concentration of 1250 µg/ml of ORN and labeled as Standard Stock ORN. Mix Standard Solution 50 mg of standard OFL and 125 mg of standard ORN were weighed and transferred to a 100 ml volumetric flask and dissolved in 35 ml of mobile phase. Then volume was made up to the mark with same solvent to obtain final concentration of 500 µg/ml of OFL and 1250 µg/ml of ORN. The solution was labeled as Standard Stock MIX-A. Calibration curves for OFL and ORN From the Standard Stock MIX-A, mixed standard solutions of different concentration ranging from µg/ml and µg/ml for OFL and ORN respectively were prepared by diluting with mobile phase. With the optimized chromatographic conditions, a steady baseline was recorded. 20 µl of each mixed standard solution was injected six times and chromatograms were recorded. The retention time of OFL and ORN were and 5.69 min respectively. Calibration curves were constructed by plotting the average peak areas against the respective concentrations (Fig. 3 and 4). Fig. 3. Calibration curve for ofloxacin.

1974 Int J Pharm Sci Nanotech Vol 6; Issue 1 April June 2013 Fig. 4. Calibration curve for ornidazole. Fig. 5. Chromatogram of ofloxacin (peak 2) and ornidazole (peak 1).

3 1974 Int J Pharm Sci Nanotech Vol 6; Issue 1 April June 2013 Fig. 4. Calibration curve for ornidazole. Fig. 5. Chromatogram of ofloxacin (peak 2) and ornidazole (peak 1). Analysis of Marketed Formulation Amount equivalent to about 5 ml of O2-Suspension containing 50 mg of OFL and 125 mg of ORN was weighed accurately and transferred carefully to 100 ml volumetric flask, then the volume was made up to the mark with mobile phase to give a solution of 500 µg/ml of OFL and 1250 µg/ml of ORN. The resulting solution was filtered through Whatmann filter paper No. 41 and this solution was used as Sample Stock AV. From this solution 2 ml of the aliquot was pipetted out and transferred to a 25 ml volumetric flask. The volume was made up to the mark with mobile phase to obtain a solution with final concentration of 40 µg/ml of OFL and 100 µg/ml of ORN. Similarly, from the Standard Stock MIX-A (500 µg/ml of OFL and 1250 µg/ml of ORN) solution 2 ml of aliquot was pipetted out in a 25 ml volumetric flask. The volume was made up to the mark with mobile phase to obtain a solution with final concentration of 40 µg/ml of OFL and 100 µg/ml of ORN. Both solutions were filtered through 0.45µm cellulose acetate filter using syringe and injected into the Rheodyne injector (20 µl) of HPLC system and their chromatograms were recorded (Fig. 5) under the finalized chromatographic conditions as described above after getting a stable baseline. Method Validation The method was validated for various parameters as per ICH Guidelines (International Conference on Harmonization, 2005; USP, 2005).

4 Varun et al: RP-HPLC Method for the Quantitative Estimation of Ofloxacin and Ornidazole in Liquid Oral Dosage Forms Accuracy The accuracy of the method was determined by recovery experiment, Recovery studies were carried out by standard addition method by adding the known amount of OFL and ORN (reference standard) to the preanalyzed sample at three different concentration levels i.e. 80%, 100%, and 120% of assay concentration and percent recoveries were calculated. From the above sample Stock AV (500 µg/ml of OFL and 1250 µg/ml of ORN) solution 2 ml of the aliquot was pipetted out and transferred to three different 25 ml volumetric flasks separately along with 1.6, 2.0, 2.4 ml of aliquot from the Std Stock MIX-A (500 µg/ml of OFL and 1250 µg/ml of ORN) solution. The volume was made up to the mark with mobile phase. All the solutions were filtered through 0.45 µm cellulose acetate filter using syringe and injected into the Rheodyne injector (20 µl) of HPLC system and their chromatograms were recorded. The percentage recovery and standard deviation of the percentage recovery were calculated. 2. Precision Precision was studied to find out intra and inter day variation in the proposed method at three different levels on the same day and on three different days, respectively. The % RSD was calculated for intraday and inter-day precision. 3. Linearity and Range The linearity of analytical method for OFL and ORN were determined by studying standard calibration curves. The range of analytical method was decided from the interval between upper and lower level of calibration curves by plotting the log curve. 4. Limit of Detection and Limit of Quantitation Detection limit and quantitation limit were determined based on the standard deviation of y- intercepts of six calibration curves and average slope of six calibration curves. Standard deviation of intercept LOD = 3.3 Slope Standard deviation of intercept LOQ = 10 Slope 5. Robustness Combined standard solutions of OFL (40 µg/ml), ORN (100 µg/ml) were prepared and analyzed at different ph (2.33, 2.4, 2.47) and at different flow rate (0.97, 1.00, 1.03 ml/min) and at different mobile phase ratio (84:16, 87:13, 90:10 v/v) separately. 6. System Suitability Sample solutions of OFL (40 µg/ml) and ORN (100 µg/ml) were prepared and analyzed. Chromatograms were studied for different parameters such as tailing factor, resolution and theoretical plates to see that whether they comply with the recommended limit or not. Results and Discussion For chromatographic separation, solvent system using combinations of potassium dihydrogen phosphate (KH2PO4) and acetonitrile (ACN) at various proportions and ph were investigated. Changing the ratio of the mobile phase and its ph, a change in the retention time and peak area of the drugs were observed. Out of various combinations, mobile phase containing mixture of KH2PO4 buffer: ACN (87:13 v/v) at ph 2.4 adjusted with 1% orthophosphoric acid, at a flow rate of 1 ml/min with UV detection at 294 nm, using phenyl column as a stationary phase was finalized. The retention time of OFL and ORN were and 5.69 min respectively. The overlain spectra of OFL and ORN showed absorbance at 294 nm hence detection was carried out at 294 nm. The linearity of analytical method at six concentration levels was ranging from µg/ml and µg/ml for OFL and ORN respectively and is presented in Table 3. The regression equation of calibration curves were Y= x and Y= x for OFL and ORN respectively (Fig. 3, Fig. 4). The results show that an excellent correlation exists between response factor and concentration of drugs within the concentration range. The LOD was found to be µg/ml for OFL and µg/ml for ORN. LOQ was found to be µg/ml for OFL and µg/ml for ORN. Assay results were satisfactorily obtained and were found to be 99.86% for OFL and 96.44% for ORN, as they were compared with the labeled amounts (Table 1). The % recovery values for accuracy study indicated that the developed method was found to be accurate. The results are shown in Table 2. In repeatability study, % RSD was found to be for OFL and for ORN. At all three concentration levels, precision showed satisfactory levels. Results of intermediate precision study, % RSD values for each set (all three levels) were found to be < 3 % indicating that these methods have excellent repeatability and intermediate precision. For, robustness it was observed that there were no marked changes in the retention time and the area of the chromatograms and the % RSD was less than 3 %, which demonstrated that RP-HPLC method developed was robust. The results for validation and system suitability test parameters are summarized in Table 3. The method gives good resolution between the compounds with a short analysis time. TABLE 1 Assay results of O2 suspension by RP-HPLC method. Amount Present Amount Found Sr. % Assay (mg/5ml) (mg/5ml) No. OFL ORN OFL ORN OFL ORN Mean ±SD %RSD OFL is Ofloxacin, ORN is Ornidazole, % Assay is percentage assay, SD is Standard Deviation for n=3 observation, RSD is Relative Standard Deviation.

5 1976 Int J Pharm Sci Nanotech Vol 6; Issue 1 April June 2013 TABLE 2 Validation data for accuracy study. Level of % Recovery Mean (% Recovery) ±SD %RSD OFL ORN OFL ORN OFL ORN 80% % % Mean is Mean of 3 estimations, SD is Standard Deviation for n=3 observations, RSD is Relative Standard Deviation. TABLE 3 Results of validation and system suitability parameters. Parameters OFL ORN Linearity Range (μg/ml) Regression Equation x x (y = mx+c) Correlation Coefficient (r 2 ) LOD (μg/ml) LOQ (μg/ml) Intra Day Precision (% RSD) Inter Day Precision (% RSD) Repeatability (%RSD) Robustness (%RSD) < 3 % < 3 % Retention Time (min) Tailing Factor (T) Theoretical Plates (N) Resolution (R) OFL is Ofloxacin, ORN is Ornidazole, y = mx+c where y is absorbance, m is slope, c is intercept, LOD is Limit of Detection, LOQ is Limit of Quantitation, RSD is Relative Standard Deviation, % is percentage, min is minute, <3% is Less than three percentage. In conclusion the present work states a simple innovative method for quantitative estimation of Ofloxacin and Ornidazole in combined liquid oral dosage form. In the formulation taken for study the sample recovery was found to be in good agreement with the label claims, indicating non-interference of excipients in the estimation. The method was validated and found to be simple, sensitive, accurate, precise and robust. It can, therefore, be easily and conveniently adopted for routine quality control analysis of raw materials and formulations. Acknowledgements The authors are grateful to Dodel Analytical Lab., Vapi, Gujarat, for providing samples of ofloxacin, ornidazole and facilities for carrying out this research work. The authors thank Mr. Kishorbhai Mehta and Shashibhai for their valuable contribution. References Barot HN, Dave JB and Patel CN (2012). Development and validation of spectrophotometric method for simultaneous determination of Prednisolone acetate and Ofloxacin in eye drop. Int J Pharm Sci Res 3: Darshan S, Smita T and Mandev P (2012). Simultaneous estimation of Cefpodoxime proxetil and Ofloxacin in pharmaceutical dosage form by RP-HPLC. Int J Pharm Pharm Sci 4: Daxina KL, Shah SA, Shah DR, Marolia BP, Vaghela MP and Ravalji MB (2011). Simultaneous estimation of Ornidazole and Ofloxacin by derivative spectrophotometry method. Int J Chem Anal Sci 2: Indian Pharmacopoeia (2010). 6 th ed. Controller of Publication, Govt. of India, Ministry of Health and Family Welfare, New Delhi. International Conference on Harmonization, (2005). Q2 (R1), Harmonised Tripartite Guidelines, Validation of Analytical Procedures: Text and Methodology, Geneva. Jawed A, Birendra S, Parth B, Ankur P and Vikas T (2011). Simultaneous estimation of ofloxacin and ornidazole in synthetic mixture by Q-analysis UV spectrophotometric method. Asian J Pharm Life Sci 1: Kareti SR, Arijit B and Nargesh KK (2011). Spectrophotometric methods for the simultaneous estimation of ofloxacin and tinidazole in bulk and pharmaceutical dosage form. Chron Young Sci 2: Nalini CN, Ramachandran S, Kavitha K and Harikrishna (2011). Simultaneous determination of Ofloxacin and Ornidazole in tablets by Spectrophotometry and RP-HPLC. Res J Pharm Biol Chem Sci 2: Pankaja SK, Niranjan MS, Chaluvaraju KC and Rajendra CE (2012). Method development and validation for the simultaneous estimation of Moxifloxacin Hydrochloride and Ornidazole by RP- HPLC. Int J Pharm Res Dev 4: Puranik M, Bhawsar DV, Rathi P and Yeole PG (2010). Simultaneous determination of ofloxacin and ornidazole in tablet dosage form by RP-HPLC and HPTLC method. Indian J Pharm Sci 72: Ramesh J, Arul Prakasam KC, Suresh A and Venkatesh K (2011). Development and validation of simultaneous equation method for the estimation of Cefexime and Ofloxacin in pure and in tablet formulation. Int Res J Pharm 2: Rege PV, Sathe PA, Salvi VS and Shotri CK (2011). Simultaneous spectrophotometric estimation of ofloxacin and ornidazole from combined tablet dosage form. Int J Pharm World Res 2: Rege PV and Ramesh M (2011). Simultaneous quantification of Ofloxacin and Ornidazole from combined pharmaceutical drug formulation by HPLC. Int J Pharm Bio Sci 2: Rege PV and Sathe PA (2011). Simultaneous quantification of Ofloxacin and Ornidazole in combined drug formulation by a simple electro analytical technique. Int J Pharm Sci Res 2: Tripathi KD (2008). Essentials of Medical Pharmacology, 6 th ed. Jaypee, New Delhi. USP (1990). The United State Pharmacopoeia/The National Formulary, USP XXII/NF XVII, United State Pharmacopeial Convention, Inc;1990. Address correspondence to: Mrs. Cylma Menezes, Assistant Professor, Department of Quality Assurance, Shree Devi College of Pharmacy Airport Road, Kenjar, Mangalore , Karnataka, India. cylmar@rediffmail.com Tel:

IJRPC 2013, 3(1) Gandhi et al ISSN: INTERNATIONAL JOURNAL OF RESEARCH IN PHARMACY AND CHEMISTRY

IJRPC 2013, 3(1) Gandhi et al ISSN: INTERNATIONAL JOURNAL OF RESEARCH IN PHARMACY AND CHEMISTRY INTERNATIONAL JOURNAL OF RESEARCH IN PHARMACY AND CHEMISTRY Available online at www.ijrpc.com Research Article DEVELOPMENT OF UV-SPECTROPHOTOMETRIC METHOD FOR THE QUANTITATIVE ESTIMATION OF OFLOXACIN AND